Our objectives are to explore the relationships among immunostimulation, immunosuppression, virus activation, autoimmunity and oncogenesis in murine models and in man. Immunological activation of C-type oncornaviruses and cytomegaloviruses have been demonstrated in mice, and similar events are being explored in humans in post-transfusion mononucleosis, during pregnancy, and following renal transplantation. The ability of humans to mount cell-mediated responses against primate oncornaviruses is being examined. Studies of the efficacy of interferon prophylaxis in renal transplant recipients are underway. Cytomegalovirus-leukocyte interactions are being explored in vitro. BIBLIOGRAPHIC REFERENCES: Hirsch, M.S. Interactions between C-type oncornaviruses and lymphocytes. In: Mechanisms of tumor immunity (Ed. I. Green, R. McCluskey, S. Cohen) Wiley & Sons, Inc., New York, 1977, pp. 287-303. Keller, E.W., Hierholzer, J.C., Rubin, R.H., Black, P.H., Hirsch, M.S. Isolation of adenovirus type 34 from a renal transplant recipient with interstitial pneumonia. Transplant. 23:191-193, 1977.